Hi, my name is Cristina and my english is not really good (sorry) I am from Spain and I was working in Gis. Now I am in Australia, and I have some questions. I need to start my new project here in Australia with arcgis 10 (before 9.1). And I want to know if I can find free cartography from Australia (rivers, national parks, aerial photos...).
The second question is if Australia use Geographic cooridante system or Projected coordinate system
Check out Geoscience Australia. They have some free data downloads and information on the coordinate systems in use. The current geographic coordinate system is GDA 1994, with earlier ones, AGD 1966 and AGD 1984. There are UTM-like zones, "Map Grid of Australia" aka MGA, based on GDA 1994.
There are a few national projected coordinate systems too, plus some state-based ones. Check state GIS sites for data too.